1. Field of the Invention
The present invention relates to an X ray detecting device using a semiconductor device.
2. Description of the Prior Art
In a roentgen diagonal device for taking a radioscopy picture of a patient, there is used an X ray detecting device for measuring the intensity of the X rays to control the intensity of the X ray radiation from an X ray source. The X ray detecting device mentioned above is usually disposed between the X ray source and the patient.
There has been proposed such an X ray detecting device comprising an X ray to light converting unit (referred to as an XL converter) for converting the incident X rays into visible light and a light to electric converting unit (LE converter) for converting the visible light into an electric signal, so that the intensity of the X rays can be measured by the electric signal. In the conventional X ray detecting device of the above type, the LE converter is formed by using a base plate made of glass or metal. The X rays passing the X ray detecting device are attenuated by the base plate made of glass or metal, whereby the amount of the X rays to be radiated on the patient decreases and an unnecessary image of the base plate of the LE converter appears on the radiography of the patient and therefore a clear patient's radiography cannot be obtained. In order to prevent the appearance of the image of the base plate of the LE converter on the radiography in the conventional device, it is necessary to use a large X ray detecting device having a large LE converter which is larger than the object to be radiographed. In order to accomplish this purpose, if there is provided a large X ray detecting device, it is unreasonable to use the large size X ray converter having a large size LE converter to radiograph a relatively small sized object. In addition the large size LE converter causes the weight of the X ray detection device to be heavy and the operability of the X ray detection device becomes deteriorated.